A typical dairy has thousands of head of dairy cows. These cows being housed, fed, and milked at the dairy. In such a typical operation, the dairy cows will be held within lots, these lots often having concrete pad portions. The dairy would likewise have a dairy barn/milk room/parlor wherein the twice daily milking of the cows takes place. Such a parlor likewise having a concrete floor.
Diary cows, like any animal, generate a substantial quantity of liquid (urine) and solid (dung) waste. To protect milk quality and for sanitation purposes, the waste with the parlor is frequently washed out, using a spray of water. Likewise, the concrete pad areas in the lot themselves are periodically washed, and further, rainwater serves to run off such surfaces. Such water, whether it be through washing out the parlor, normal diary drainage, washing off the lot surface, and/or rainwater runoff, becomes a source of wastewater effluent within a wastewater management system.
This wastewater effluent containing fibrous materials (loose straw, hay, undigestible materials), urine, solid fecal matter and other materials. As such, this wastewater effluent has an odor and contents which pose a significant environmental risk (bacterial and nutrient load) if left untreated. As a result, dairies typically treat and/or store this wastewater effluent.
An unregulated dairy might merely discharge its wastewater effluent into the environment, thereby causing a major source of pollution to the soil, ground water and/or surface water. Such an action would not be possible under current federal and state regulations. A second way a dairy might handle wastewater effluent would be to store it within lagoons, storage ponds, and other impoundments. A third way would be to apply the wastewater effluent to crops for uptake by the plants of the nutrients contained therein. All three of these methods would result in both a substantial source of odor, as well as the related environmental concerns. Further, such systems can use a considerable amount of water, at a significant cost to a dairy.